Feeding mechanism for sewing machines



Feb. 28, 1933. K MAlER I 1,899,816

FEEDING MECHANISM FOR SEWING MACHINES:

Filed Dec. 16, 1927 2 36 9)]. V 2 Z g 14 I I l? I Z J )1 I M F 16 la I Patented Feb. 28, 1933 UNITED STATES PATENT OFFICE KARL IAIEB, OI S'IUTTGABI, GEBIANY, ASSIGNOB- T0 UNION SPECIAL KASGHINEN- I'AIBBIK, G. I. B. 3., OF STUTTGABT, GERMANY FEEDING MECHANISM FOR SEWING HACH INES Application filed December 16, 1827, Serial Ho. 240,583, and in Germany February 25, 1927.

The invention relates to new and useful improvements in feeding mechanism for sew ing machines, and more particularly to a feeding mechanism is moved back and forth and raised and lowered for imparting feeding movements to a feed dog.

It has been a common practice to provide a cam which is located adjacent the free end of the feed bar of a four-motion feeding mechanism for raising and lowering the feed ba and the feed bar has a movement in an endwise direction back and forth on the cam. Inasmuch as the cam is adjacent the stitching point, it has been found in practice that dust, threads and other residues lodge on the faces of the parts of the feed bar which engage the cam, and pass in between the cam and the bearing faces, thus affecting the smooth run ning of the feeding mechanism.

An object of the present invention is the provision of means for housing the cam without interfering with the back and forth movements of the feed bar so as to protect the bearing faces between the cam and the parts engaged thereby.

further object of the invention is to provide a housing means of the above type which is also provided with devices for wiping the bearing faces at the outer end of the feed bar, and for preventing dust, lint and the like from passing along the bearing faces and between the same and the cam. A still further object ofthe invention is to provide a housing means of the above ty with a lubricating means for lubricating t e cam and the bearing faces of the feed bar.

A still further object of the invention is to provide a feeding mechanism of the above type with an oil retaining'pa-d so disposed that as the feed bar'moves relative to the housing, oil will be delivered therefrom to the lubricating means carried by the housing.

These and other objects will in part be obvious and will in part be hereinafter more fully described In the drawing which shows by way of illustration one embodiment of the invention: Figure 1 is a view partly in section and partly in elevation showing a portion of a having a feed bar which four-motion feeding mechanism for sewing machines.

Fig. 2 is an enlarged longitudinal sectional view on the line AB of Fig. 3.

Fig. 3 is a sectional view on the line CD of Fig. 2.

The invention is directed to a feeding mechanism for sewing machines of thefourmotion type, wherein a feed dog is mounted on a feed bar which is not only moved back and forth, but which is raised and lowered at the free end thereof, and thus imparting four motions to the feed dog. The feed bar is raised and lowered by a cam at the free end of the feed bar. A fork mounted on the feed bar extends beneath the cam so that the feed dog carried at the free end of the feed bar is positively raised and lowered by said cam. A housing is provided for said cam, which housing is located between the feed bar and the fork, and is free to move back andforth relative to the feed bar as the cam rotates. This housing includes an outer plate covering the front side of the cam, and a rear plate covering .the rear side of the cam. These two lates are joined by supporting bridge mem ers which are properly formed so as to permit the shaft of the cam to rotate freely in the housing. The outer plate is provided with oil ads arranged to engage the bearing faces 0 the feed bar and fork at the upper and lower sides of the housing, so

as to revent any dust, dirt or lint from acoiling pad is arranged in conjunction with said rear plate so as to lubricate the cam.

Between the housing and the rear end of the fork is a lubricatin pad which is so positioned as to be presse upon by the housing during the operation of the feeding mechanism, and thus it is that the oil contained in said pad will be transferred to the lubricating pad carried by the housing.

Referring more in detail to the drawing, the invention is shown as applied to a sewin machine which includes a bed plate 6. A fee rocker 3 of the usual type is mounted on a pintle 4 located in bearing lugs 5 carried by the bed plate 6. The feed bar is indicated at thereon. Carried by the feed bar is a fork 1 in the drawing and said feed bar is connected to the upper end of the feed rocker 3 by a pintle 2. At the other end of the feed bar is a feed dog? which is secured'to the feed ar, so that it may be adjusted vertically 10 which is secured to the feed bar by suitable screws. The main shaft of the sewing machine is indicated at 9. Mounted on. said shaft is a cam8. Said cam bears against the plate 11 attached to the free end of the feed a r 1 by suitable screws and becoming a part of the feed bar. The cam also bears against the upper face of the fork 10.

As the main shaft rotates the cam will cause the feed bar at the free end thereof to rise and fall, thus moving the feed dog into and out of engagement with the material. The feed rocker as it oscillates will move the feed bar back and forth, and thus impart feeding movements to the feed dog. The parts as described are of the usual construction, and the invention is directed to a housing means for the cam which operates the feed bar' to prevent dirt, lint and dust from working in between the bearing faces of the parts carried by the feed bar and the cam which raises and lowers the feed bar.

- This housing means includes a plate 12 atthe front side of the cam and a plate 12 at the rear side of the cam. These two plates are connected by bridging plates or members 13,

13, one at each end of the housing. The plates.

13, 13 are securedto the plates 12, 12 by suitable screws. Each of the plates 12, 12 is provided with inwardly extending angle members so as to provide an' extended bearingface adapted to cooperate respectively with the plate 11 and the fork 10.

The bridging members 13, 13 are each provided with an opening 14. The shaft passes through this opening and the opening is sufficiently large so as to permit the housing to On the front plate 12 there is a retaining member 15 provided with outwardly bent ortions at its upper and lower sides which orm pockets for oiling pads .17 17. These oiling pads are located so as to engage respectively the under and upper faces of the 7 plate '11 and the fork 10 when the feed bar is at the forward end of its stroke. These oiling pads wipe these bearing faces and keep 3: same free from dust, dirt, lint and the vMounted on the plate at therear side of the cam is a retaining member 16 which is provided with outwardly bent portions providing pockets for further oiling pads 17, 17. These oiling pads make contact with the under and upper faces, respectively, of the plate 11 and fork 10. Thesepads will prevent dust, dirt, lint and the. like from working into the housing. This rear plate 12 is also provided with a member 18 which forms a pocket for a lubricating pad 20. The plate 12 at the rear is provided with openings 21, 21 through which this pad 20 projects, so as to make contact with the cam 8. A lubricating ad 22 is placed in the rear portion of the for 10 and up against the rear wall 23 of the fork. This pad is saturated with oil and is of suflicient size so that during the back and forth movements of the feed bar the pad 20 carried by the housing will press against the pad 22, and thus the pad 22 will be squeezed and a portion of the lubricating oil transferred to the lubricating pad 20.

From the above it will be apparent that a housing has been provided for the cain which raises and lowers the feed bar in a fourmotion feed mechanism, which housing not only protects the bearing faces between the cam and the parts carried by the feed bar from dirt dust, lint and the like, but the housing also serves as a medium for freely lubrieating the cam.

It will be obvious that minor changes in the detail of construction and arrangement of parts may be made without departing from the spirit of the inventionas set forth in the appended claims.

What is claimed as new is:

1 A four-motion feeding mechanism for sewing machines including in combination a feed bar, a feed dog carried thereby, said feed bar having a forked bracket attached there- I forked bracket for raising and lowering said feed bar, a plate located in front of said cam for shielding the-same from dust, lint and dirt, said plate being movable up and down with thefeed bar, and means. for supporting lubricating pads at the upper and lower edges of said plate which are adapted to contact to, a cam located between the feed bar and the I with the feed bar and the forked bracket respectively to keep the dust, lint and dirt away 7 from the cam.

2. A four-motion feeding mechanism for sewing machines including in combination a feed bar, a feed dog carried thereby, a forked bracket carried by said feed bar, a cam between the'forked bracket and the feed bar for raising and lowering the fed bar, a-housing located between said forked'bracket and the feed bar for said cam, said housing being movable up and down with the feed bar and back and forth relative to the feed bar, and pads carried by the housing and projecting therefrom and adapted to engage said feed bar and the forked bracket respectively.

3,. A four-motion feedin mechanism for sewing machines including in combination a feed bar, a feed dog carried thereby, a forked bracket. carried by said feed bar, a cam between the forked bracket and the feed bar for raising and lowering the feed bar, a housing located between'said forked bracket and the feed bar and substantially enclosing said cam, said housing being movable u and down with the feed bar and back and orth relative to the feed bar, and pads carried by the housing and projecting therefrom and adapted to engage said feed bar and the forked bracket respectively, said housing at the rear of the cam having openings therethrough, and means for supporting a lubricating pad which is adapted to make contact with the cam through said openings.

4. A four-motion feeding mechanism for sewing machines including in combination a feed bar, a feed dog carried thereby, a forked bracket carried by said feed bar, a cam between the forked bracket and the feed bar for raising and lowering the feed bar, a housing located between said forked bracket and the feed bar and substantially enclosing said cam, said housing being movable up and down with the feed bar and back and forth relative to the fed bar, pads carried by the housing and projecting therefrom and adapted to engage said feed bar and the forked bracket respectively, said housing at the rear of the cam having openings therethrough, means for supporting a lubricating pad which is adapted to make contact with the cam through said openings, and a lubricating pad located in said forked bracket in rear of the housing and adapted to be engaged by the pad on the housing when said feed bar moves back and forth.

5. A four-motion feeding mechanism for sewing machines including in combination a feed bar, a feed dog carried thereby, a forked bracket carried by said feed bar, a cam between the forked bracket and the feed bar having a peripheral portion engaging said feed bar and bracket for raising and lowering the feed bar, a housing located between the forked bracket and the feed bar, said housing being movable up and down with the feed bar and back and forth relative to the feed bar and constructed so as to enclose the perigheral portion of the cam.

11 testimony whereof, I atfix my signature.

. KARL MAIER. 

